Hydrocarbon fuels containing sulfonate antifreeze compositions



HYDROCARBON FUELS CONTAINING SUL- FONATE ANTIFREEZE COMPOSITIONS Emil A. Vitalis, Springdale, and Frederick L. Andrew,

Ice 2,886,422

Patented May 12, 1959 Low temperature characteristics, ice crystal and solid wax formation and freezing points of liquid fuels, and

' Glenbrook, 'Conn., assignors to American Cyanamid Company, New York, N.Y., a corporation of Maine No Drawing. Application June 28, 1956 Serial No. 594,371

3 Claims. (Cl. 52-.5)

The present invention relates to liquid fuel compositions having improved low temperature characteristics and particularly jet fuels, are important factors leading to the acceptance thereof and this is especially so in military service and cold weather operations wherein the requirements are rigorous and varied.

Low freezing point values have been required in order to provide maximum pumpability of the liquid fuel in the aircraft or like fuel systems under extremely frigid conditions or at very high altitudes and to avoid the formation of ice crystals in the fuel whereby its low more specifically is concerned with kerosene, gasoline, diesel and turbo-jet fuel compositions having lower freezing points and wherein the formation of ice crystals and the separation of wax and other solids is prevented until substantially lower temperatures are reached.

Petroleum hydrocarbons have been established as the I presently preferred fuels for spark-ignition engines, compression-ignition engines and jet-propulsion engines, the latter including the gas-turbine type of power plant, particularly employed for aircraft propulsion purposes. As

used herein, these petroleum hydrocarbons fall into several loosely-defined classes of which the following are pertinent to the present invention: (1) aviation gasoline, the petroleum fraction boiling between about 100 and about 330 F.; (2) motor gasoline, the petroleum fraction boiling between about 100 F. and about 430 F.;

(3) kerosene and diesel fuel,-the fraction boiling between about 300 and 625 F.; and (4) jet fuel, the fraction boiling between about 100 and about 600 F. and preferably between about 150 and about 550 F. All these products may be made up of straight run, thermally cracked and/ or catalytically cracked components. With particular reference to kerosene and jet fuels which are illustrative but not limitative of the present invention, such'products possess desirable characteristics of flammability, engine power requirements, freezing points, flash points, vapor loss, cost and availability which have rendered them most suitable for the fuel for jet aircraft. Aviation kerosene is a blend of petroleum fractions and is made to meet a variety of specifications. The following data are presented to illustrate one particular commercial product:

temperature behavior is seriously affected. At certain temperatures, fuels may contain up to 0.015 percent by weight of water dissolved in the fuel which, as the fuel temperature is reduced and its water solubility decreased, could lead to the separation of water and the undesirable formation of ice crystals. The possibility of blockages, such as in fuel filters, carburetors, and other operational equipment, is created with resulting engine failures.

The principal object of the present invention is the provision of liquid fuel compositions of the type described above wherein improved low temperature characteristics as indicated by a reduced cloud point are obtained by in-' corporating therein both an aliphatic monohydric alcohol and an alkali metal salt of a sulfonated aliphatic or alkaryl hydrocarbon as hereinafter more fully described.

We have found a synergistic action of certain monohydric alkanols in admixture with alkali metalsalts of certain sulfonated hydrocarbons of approximately 12-30 carbon atoms which results in materially reduced cloud points when they are incorporated into liquid petroleum fractions of the above-described types having boiling points between about 100 F. and 625 F. The aliphatic alcohols which we have found suitable for this purpose are the monohydric alkanols of from 2 to 3 carbon atoms; i.e., ethanol, propanol and isopropanol. The alkali metal sulfonates used in conjunction with these alcohols are the alkali metal salts of petroleum sulfonates, alkylated monocyclic aromatic hydrocarbon sulfonates containing an alkyl radical of about 10-22 carbon atoms and alkylnaphthalene sulfonates containing an alkyl radical of Distillation (20% evap.) F. max 392 End point F. max 572 Residue, percent volume max 2.0 Loss, percent max 1.5 Sulfur, percent wt. max. 0.2 Freezing point F --40 B.t.u./lb. net, min. 18,300 Flash point F..-

' Larger quantities of the alcohol-sulfonate mlxture can of Similarly, turbo-jet fuels are blends of petroleum fractions and are made to meet a variety of specifications. The following data are presented to illustrate one particular product, namely, JP-4, which is a wide-cut petroleum fraction covering the boiling range of both gasolines and diesel fuels.

Flash point F-.. 10

from about 3 to about 18 carbon atoms. The alcohol or alcohol mixture and the alkali metal sulfonate are preferably used in weight ratios within the range of from 1:4 to 4:1. Our invention in its broadest aspects therefore consists in the provision of liquid hydrocarbon fuels of petroleum origin having the boiling point range indicated above and containing the alcohol and hydrocarbon sulfonate mixture in quantities sufiicient to reduce the cloud point thereof. I

Although we have noted an appreciable lowering of the cloud points of the liquid hydrocarbon fuels when as little as 0.01% by weight of the above-described mixtures are added thereto, minimum quantities of about 0.1% of the weight of the hydrocarbon fuel are preferred.

course be used to reduce still further the cloud points of the liquid fuel compositions up to maximum quanti- =ties within the range of about 3% to 5% by weight. Larger quantities than these maxima are not recommended, as they may tend to crystallize out of the fuel at very low temperatures. The term cloud-point reducing quantities as used herein is therefore intended to designate quantities within the range of about 0.1-3% on the weight of the hydrocarbon fuel with somewhat larger amounts up to about 5% being permissible in special cases.

It is an important advantage of our invention that representative and effective alkali metal sulfonates of the above-described types are available commercially in large quantities and at a relatively low cost. The petroleum sulfonates, for example, are typified by Twitchell oil and mahogany sulfonates, both of which are produced commercially in large quantities. The alkylbenzene and alkyltoluene sulfonates are in wide commercial use as anionic surface-active agents and detergents, and any of these may be used. The alkylnaphthalene sulfonates are also well-known anionic surface-active agents and are easily prepared by alkylating naphthalene sulfonic acids such as naphthalene beta sulfonic acid with isopropyl and butyl alcohols or with isopropyl and butyl chlorides and then neutralizing with an alkali metal hydroxide or carbonate. Sulfonation products of alkylnaphthalenes obtained by condensing naphthalene with propylene, butylene or polymers thereof in the presence of aluminum chloride or other Friedel-Crafts catalysts may also be employed. In most cases the monosulfonates of these and similar alkaryl hydrocarbons are used in practicing the invention.

Typical sulfonates which may be used in the form of their alkali metal salts are the following:

(1) Sulfonated condensation products of chlorinated kerosene fractions of from 10 to 18 carbon atoms with monocyclic aromatic hydrocarbons such as benzene, toluene and xylene prepared as described in US. Patents Nos. 2,233,408 and 2,340,654. Typical products are sodium dodecyl benzene sulfonate (Igepal NA") and potassium dodecyl Xylene sulfonate (Emulphor STX").

(2) Sulfonated condensation products of propylene or butylene polymers of 9 to 18 carbon atoms with benzene or other monocyclic aromatic hydrocarbons. Typical compounds are the sodium dodecyl benzene sulfonate and sodium octadecyl benzene sulfonate prepared by condensing a propylene polymer with benzene in the presence of hydrofluoric acid followed by sulfonation with 100% H 50, and 20% oleum and neutralization with sodium hydroxide.

(3.) Alkylnaphthalene sulfonates produced by sulfonating alkylnaphthalenes or by condensing naphthalene monosulfuric acids with aliphatic alcohols of from 3 to 8 carbon atoms. Typical compounds are the butylated naphthalene sulfonates described in US. Patent No. 1,933,068.

(4) Water-soluble alkali metal petroleum sulfonates such as Twitchell oil.

(5) Oil soluble alkali metal petroleum sulfonates such as mahogany sulfonates.

The standard test used to evaluate the effect on the low temperature characteristics and properties of fuels is as follows: The surface-active agent and the alcohol were added individually or jointly to the selected fuel in the ratio indicated in the tables. The liquid fuel was then slowly cooled with constant stirring to avoid local temperature efiYects and was observed very closely during the cooling for the development of cloudiness or haziness due to the appearance of minute ice or wax crystals. The procedure was then .reversed and the fuel allowed to warm slowly and observations taken as to the melting of the ice crystals and the disappearance of cloudiness or haziness. All tests were run at standard atmospheric pressure.

Samples of the IP-4 fuel described above were tested in this manner after adding 0.5% by weight of the mixtures tabulated below along with control samples containing no additive or containing the alcohol only. The percentages shown are by weight; the test results were as follows: 5

Cloud Points Additive Mixture Cooling Becomes Warming- Turbid, Clears, F. 10 F.

1 None-(Control) +32 +40 2"--. Ethanol only (0.5%) +32 +40 3 Isopropanol only (0.5%) +32 +40 4 [25% Na keryl benzene sulfonate- +10 5 [75% Isopropanol 5 25% Na dodeeylbenzene sulfonate 75% Isopropanol 6 25% Na octadecylbenzene sulionate a.0 -23 -s 9 ligh q t r'is -30 +10 a on a ecy enzene s ona e ;ggi gn 26 W1 0 e O 75%, Ethanol 28 1 Prepared from propylene polymers.

What we claim is:

1. A liquid fuel of improved low temperature characteristics consisting essentially of a petroleum, fraction boiling between about 100 F. and 625 F. containing cloud point-reducing quantities within the range of about 0.13% of (1) an alkali metal salt of a member of the group consisting of petroleum sulfonates, monosulfonated alkylated monocyclic aromatic hydrocarbons containing an alkyl radical of from 10 to 18 carbon. atoms and monosulfonated alkylnaphthalenes containing an alkyl radical of from 3 to 18 carbon atoms and (2) a monohydric alkanol of from 2 to 3 carbon atoms, the weight ratio of (1) to (2) being within the range of from 1:4 to 4:1.

2. A liquid fuel of improved low temperature characteristics consisting essentially of a petroleum fraction boiling between about 100 F. and 625 F. containing cloud point-reducing quantities within the range of about 0.143% of an alkali metal petroleum sulfonate and a monohydric alkanol of from 2 to 3 carbon atoms in a weight ratio of from 1:4 to 4:1.

3. A liquid fuel of improved low temperature characteristics consisting essentially of a petroleum fraction boiling between about 100 F. and 625 F. containing cloud point-reducing quantities within the range of about 0..1-3% of an alkali metal alkylbenzene monosulfonate containing an alkyl radical of from 10 to 30 carbon atoms and a monohydric alkanol of from 2 to 3 carbon atoms in a weight ratio of from 1:4 to 4:1.

References Cited -in the file of this patent UNITED STATES PATENTS 2,550,982 Eberz May .1, 1951 2,626,207 Wies et al. Ian. .20, 1953 2,786,745 Stayner et a1. Mar. 26, 1957 

1. A LIQUID FUEL OF IMPROVED LOW TEMPERATURE CHARACTERISTICS CONSISTING ESSENTIALLY OF A PETROLEUM FRACTION BOILING BETWEEN ABOUT 100*F. AND 625*F. CONTAINING CLOUD POINT-REDUCING QUANTITIES WITHIN THE RANGE OF ABOUT 0.1-3% OF (1) AN ALKALI METAL SALT OF A MEMBER OF THE GROUP CONSISTING OF PETROLEUM SULFONATES, MONOSULFONATED ALKYLATED MONOCYCLIC AROMATIC HYDROCARBONS CONTAINING AN ALKYL RADICAL OF FROM 10 TO 18 CARBON ATOMS AND MONOSULFONATED ALKYLNAPHTHALENES CONTAINING AN ALKYL RADICAL OF FROM 3 TO 18 CARBON ATOMS AND (2) A MONOHYDRIC ALKANOL OF FROM 2 TO 3 CARBON ATOMS, THE WEIGHT RATIO OF (1) TO (2) BEING WITHIN THE RANGE OF FROM 1:4 TO 4:1. 